Odor free non-caking conditioned urea composition and process of preparing same

ABSTRACT

This invention relates to a novel, odor free, non-caking, conditioned urea composition and a method for the preparation thereof. More particularly, the present invention is concerned with the preparation of finely divided urea compositions in which the urea particles are treated with selected conditioners which prevent the evolution of free ammonia from the particles and accumulation of free ammonia in the area in which the particulate mass is stored and maintain said particulate mass in a non-caking condition for an extended period of time.

[ Sept. 5, 1972 ODOR FREE NON-CAKING CONDITIONED UREA COMPOSITION ANDPROCESS OF PREPARING SAME Inventors: Paul Raymond Patterson, 189 ElbertaAve., Niagara Falls, Ontario; Darryl Diamond Fry, 632 Furlong Ave.,Chippawa, Ontario, both of Canada; Irving Klothen, 215 Mount Lucas Road,Princeton, NJ. 08540 Filed: Nov. 6, 1969 Appl. No.: 874,691

Related US. Application Data Continuation-in-part of Ser. No. 724,637,April 26, 1968, abandoned.

US. Cl. ..260/555 C, 117/ 100 A Int. Cl ..C07c 127/00 Field ofSearch....260/555 C; 71/1, 28; 117/134,

[56] References Cited FOREIGN PATENTS OR APPLICATIONS 245,105 6/1960Australia ..260/555 C Primary ExaminerLeon Zitver AssistantExaminer-Michael W. Glynn Attorney-Robert P. Raymond [57] ABSTRACT Thisinvention relates to a novel, odor free, non-caking, conditioned ureacomposition and a method for the preparation thereof. More particularly,the present invention is concerned with the preparation of finelydivided urea compositions in which the urea particles are treated withselected conditioners which prevent the evolution of free ammonia fromthe particles and accumulation of free ammonia in the area in which theparticulate mass is stored and maintain said particulate mass in anon-caking condition for an extended period of time.

8 Claims, No Drawings ODOR FREE NON-CAKING CONDITIONED UREA COMPOSITIONAND PROCESS OF PREPARING SAME CROSS REFERENCE TO RELATED APPLICATIONThis is a continuation-in-part application of application Ser. No.724,637, filed Apr. 26, 1968, in the names of the present inventors, nowabandoned.

BACKGROUND OF THE INVENTION Urea finds utility in many fields ofindustry including agriculture, where it may be employed in fertilizersand animal feeds; in the chemical industry for the manufacture of avariety of organic chemicals or as a stabilizer for certain explosivesand in the plastics industry for manufacture of resins and plastics. Itis not surprising, therefore, that a substantial effort has been made toimprove the methods for the manufacture of urea and develop a productsubstantially free of problems in handling, storage and use.

Pioneers in the field of urea production early recognized that urea issubject to severe caking problems when exposed to moisture or moistatmospheric conditions and soon embarked upon programs to manufactureurea in structural forms thought to be less susceptible to caking.Through these programs such products as fertilizer prills, flakes,microprills, crystals and the like where developed. These productsshowed some resistance to agglomeration but did not alleviate theproblem to any measurable degree and other protective measures weresought.

Among the more important methods proposed for alleviating this problemwere, (1) the use of the moisture-proof bag for storage of the preparedmaterials and (2) treatment of the urea particles withsurfaceadductifying or surface-coating agents. With regard to the latterproposal, one of the most successful treatments yet available isdisclosed by T. J. Malley et al. in Canadian Pat. No. 629,423. Accordingto the patentees, particulate urea is treated with from about 0.02 to 8%by weight of a wide variety of conditioning agent. Such agents includefatty acids, fatty acid esters, fatty acid amides, fatty acid amines,fatty acid alcohols and mixtures of such agents, normal aliphatichydrocarbons having from seven to 50 carbon atoms, alkyl substitutedaliphatic hydrocarbons having from seven to 50 carbon atoms in thestraight chain and mixtures of said hydrocarbons. Although suchtreatments have generally been found to be effective for preventingcaking of particulate urea for 30 days or more, with many of theconditioners proposed for use by the patentees, it has been found thatresistance of the treated mass to agglomeration begins to diminish afterthis period. Moreover, it has been found that the proposed treatmentsare relatively ineffective for preventing the evolution of free ammoniafrom the particles and free ammonia accumulation in the area in whichproduct is stored.

Like the process of Malley et al., it has also been found that the useof the so-called moisture-proof bag" is not a cure-all for the problemsencountered in the handling and storing of urea. This measure is noteffective for preventing the evolution and accumulation of free ammoniaand may, in fact, accentuate the problem. It was surprising, therefore,to discover that a particulate urea product could be manufactured whichis extremely resistant to caking problems for a protracted period and isnot subject to the evolution and accumulation of free ammonia.

SUMMARY OF THE INVENTION The present invention relates to novel, odorfree, non-caking, conditioned urea compositions comprising:

1. at least about percent by weight of finely divided urea;

2. from about 0.1 percent to 1.0 percent by weight of methyl esterselected from the group consisting of crude cocoanut oil methyl esters,tallow fatty acid methyl esters having from about 12 to 18 carbon atoms,and the methyl esters of unsaturated fatty acids of a cis configurationcontaining from 18 to 22 carbon atoms and up to two double bonds; and

3. from about 0.01 to 0.5 percent by weight of a water soluble acidicsalt selected from the group consisting of alkali metal and ammoniumsalts of polyvalent acids having at least one replaceable hydrogen ion.The expression water soluble acidic salt, as used herein, is intended tomean that an aqueous solution of the alkali metal or ammonium salts, asdescribed above, has a pH value below 7.0.

The compositions of the present invention can be prepared by treating atleast about 95 percent by weight of finely divided urea such as ureaprills, flakes, crystals, microprills or the like, with about 0.1 to 1.0percent and preferably from about 0.25 to 0.75 percent by weight of acrude cocoanut oil methyl ester, tallow fatty acid methyl ester havingfrom 12 to 18 carbon atoms and preferably 16 to 18 carbon atoms, or amethyl ester of an unsaturated fatty acid of cis configurationcontaining from 18 to 22 carbon atoms and up to two double bonds.

Generally, the ester is applied to an agitated bed of the particulateurea as a spray or aerosol. However, it may be applied in any convenientmanner as by pouring the same into the agitated bed. Agitation iscontinued until the particles are essentially uniformly coated with theester. The other conditioners may then be added to the agitated bed ofurea or the ester coated urea may be stored until further treatment isdesirable. In practice, it has been found that storage of the estercoated urea for from 12 hours to 5 days has no deleterious effects onthe final product and may even improve its resistance to caking and theevolution and accumulation of free ammonia.

Typically the crude methyl ester of cocoanut oil is the residue from themethanol transesterified cocoanut oil from which the majority of C Cesters have been fractionated but which will contain residual amounts ofthese short-chain esters as well as all C -C esters and all still-bottomresidues such as unsaponifiable matter, residual oil and glycerin, andmay even be enriched with additional still-bottom residues from previousfractionations.

The crude tallow ester consists of the entire methanoltransesterification product without any fractionation and may beenriched with further still-bottom residues from which C and C tallowesters have previously been fractionated.

The methyl esters of unsaturated C to C fatty acids of cis configurationcontaining up to two double bonds include such materials as methyloleate (C one double bond), methyl linoleate (C two double bonds),methyl erucate (C the methyl ester of tall oil, and the methyl ester ofmenhaden oil. These esters are either available commercially or can bereadily prepared by transesterification procedures known to thoseskilled in the art. For example, the methyl ester of menhaden oil can beprepared by reacting methanol with crude menhaden oil using sodiummethoxide as a catalyst. Product is recovered by vacuum distilling thereaction mixture to a maximum of 161C. at 0.6 mm. of Hg.

Tall oil and menhaden oil methyl ester are composed of a mixture offatty acid esters with the majority of the fatty acids being unsaturatedC to C fatty acids. For example, a typical analysis of the methyl estersof tall oil and menhaden oil is shown below:

% Composition as primarily unsaturated C and C A review of the abovetable indicates that the Tall Oil methyl ester contains approximately 93percent unsaturated C -C acid, while the Menhaden Oil methyl estercontains approximately 69 percent unsaturated Cw-Cgz acid.

The preferred C C methyl esters are methyl oleate and methyl linoleate.

Attempts to successfully condition urea with saturated C to C fattyacids of a trans configuration and C to C fatty acids havingunsaturation in excess of two double bonds have been unavailing.

Following the ester coating treatment, a sufficient amount of a watersoluble acidic salt selected from the group consisting of alkali metaland ammonium salts of polyvalent acids having at least one replaceablehydrogen ion, is blended with the ester coated urea until essentiallyuniform distribution of the salt throughout the particulate mass isachieved. In practice it has been found that the amount of acidic saltrequired to give permanent protection against the evolution andaccumulation of free ammonia is equal to that required to neutralize thefree ammonia in the product plus one-half the ammonia present asammonium slats, i.e., almost exclusively ammonium cyanate. Generally,from about 0.01 to 0.5 percent and preferably from about 0.05 to 0.2percent by weight of said salt is sufficient for this purpose.Furthermore, it has been found preferable to apply such salt as a finepowder 100 percent of which is minus 100 microns.

in addition to the above treatment, it is generally desirable to blendfrom about 0.25 to 2.5 percent by weight of finely divided clay (95percent of which is minus 10 microns), and preferably kaolin, with theproduct from the above treatment. Other materials such as talc ordiatomaceous earth may be substituted for or blended with the clay,however, it is generally preferably to employ 95 percent -10 micronmaterial and in an amount not exceeding about 2.5 percent by weight oftotal composition.

Although it is usually a preferred practice to add the water solublesalt to the methyl ester coated urea particles before blending with thedesired amount of clay, we have found that the order of addition of thesalt and clay is not critical to the production of an odor free,non-caking, conditioned urea product. The order of addition of thesematerials may be reversed or they may be blended together and admixedwith the ester-coated urea particles as a uniform mix.

in order to more fully describe the present invention the followingrepresentative examples are presented which are not to be taken aslimiting but merely as illustrative of the invention.

EXAMPLE 1 Accelerated Caking Test Procedure Cylindrical test molds aremade of perforated metal 1 /ainch dia. X 2 inches high. Perforations areone-sixteenth inch on 1/8 inch centers. The open top and bottom of thecylinder are closed with discs of polyethylene, next to the test sampleand aluminum sheet, on the outside. A 50 gm. charge of the sample to betested is put into the mold, and the mold is positioned under an aircylinder which exerts a force of 3 lb./sq. in. The whole assembly isheld in a chamber, the temperature and relative humidity of which arevaried as follows:

4 Hrs. 2 Hrs.

Total exposure time is 11% complete cycles, starting and ending with thehigh temperature portion of the cycle. At the end of the exposure themolds are removed and cooled to room temperature in a desiccator. Thetop closure is then removed and the force is measured with a testingmachine which is required to force a A inch dia. rod, terminating in a60 cone, into the cake. The results of experimental conditioners (atleast 3 replicates per treatment) are presented below. In these teststhe anti-caking properties of a conditioner or treatment are evaluatedon the basis of low-crush strength and a high-caking index.

TABLE 1 Urea Mlcroprllls crush strcaking Conditioner ength, Lb. indexNone 69.1 1.0 3% kaolin 32.6 2.1 0.25% Crude cocoanut oil methyl ester8.1 8.5 0.25% Crude cocoanut oil methyl ester 2.7% kaolin 7.2 9.6 0.375%Crude cocoanut oil methyl ester 9.0 7.7 0.375% Crude cocoanut oil methylester 2.6% kaolin 4.6 15.0 0.50% Crude cocoanut oil methyl ester 3.420.3 0.50% Crude cocoanut oil methyl ester 2.5% kaolin 3.2 21.6 0.75%Crude cocoanut oil methyl ester 2.3% kaolin 5.0 13.8 0.50% Crudecocoanut oil methyl ester 2.5% kaolin 0.05% sodium bisulfate 9.9 7.00.50% methyl oleate (C 12.6 10.5 0.50% methyl linoleate (C 13.6 9.70.50% methyl erucate (C 7.9 20.6 0.50% methyl ester of tall oil C -C 7.018.9

min

5 6 0.50% meth l ester of menhad oil q -c i en 8.9 15.0 EXAMPLE 3 Todetermine the effectiveness of various agents as Caking Index Crushstrength of untreated control/Crush strength of anti-caking conditionersf! urea, 500 to 1,000 lb. sam- 53ml1e pics of feed-grade ureamicroprills, approximately 93 EXAMPLE 2 percent passing through a No. 20and retained on a No.

60 U. S. standard sieve, are treated with a variety of One thousand gramsamples of fee -grad ure agents in various combinations andconcentrations. Qp 93% 20 mesh 60 mesh, are treated With The agentstested are a crude methyl ester of palmitic a variety of ag nts an /0r cnd n rs to mpr e and oleic acid derivatives from cocoanut oil, calciumsistance thereof to agglomeration and prevent or in- 10 stearate, kaolinand guar gum. The urea microprills are hibitdevelopment of free ammoniain the treated comsprayed and/or blended in a conventional type mixerpositions. Test compositions are prepared by charging with the testagent or agents, then bagged in standard the prilled urea to a rotatingdrum, spraying the 80 lb. bags and stored. Test piles are made up byloadagitated bed of urea particles with the liquid anti-cakl 5 ing theexperimental treatments on pallets and storing ing agent and thereafterintroducing into said agitated under a weight of 2 tons. Untreated ureamicroprills, bed an appropriate amount of solid anti-caking agent baggedand stored in the same manner, are used as a or solid anti-caking agentand conditioner to prevent control. At intervals of l and 3 months aftertreatment,

accumulation of free ammonia in the treated samples. bags from eachtreatment are opened, poured onto a A When solid conditioners are usedalone in the treatinch screen and the lumps, if any present, weighed. Atment of urea prills, an appropriate amount of condisuch intervals bagsfrom each treatment are also tioner is simply blended with the urea fora sufficient dropped 3 feet, then opened, poured onto a V2 inch periodof time to assure uniform distribution of the screen and the lumps, ifany present, weighed. The conditioner in the sample. The thus preparedcomposiresults obtained appear below in Tables 3 and 4, where tions arethen placed in glass jars and sealed. At it can be seen that urea prillstreated with from about periodic intervals up to 9 days afterpreparation, each to 0.75 percent by weight of crude cocoanut ilcomposition is examined for caking and the ammonia methyl ester and fromabout 0.24 to 2.46% by weight of concentration in the confined air spaceover the samkaolin m rk ly improved resistance thereof to agples isdetermined. The results obtained are reported glomefation when bagged inConventional manner and b l i T bl 2, stored under normal storageconditions. Replacement Results obtained when other fatty acid methylester of the ude cocoanut Oil methyl ester with other conditioningagents, such as methyl oleate, methyl methyl esters such as methyloleate, methyl linoleate,

linoleate, methyl erucate, the methyl esters of tall oil methyl f r andthe methyl esters of tail and menhaden oil, and tallow, were employed wehaden 011, and tallow produced substantially similar b i ll h Same asthose Shown i T bl 2 f results to those shown for crude cocoanut oilmethyl crude cocoanut oil methyl ester. ester- TABLE 2 *Free Addi- 1Ammonia concentration in confined air space ammonia tivc over sample,p.p.m. in concenl tration, After After After Aiter After After p.p.m.Additivc(s) percent 1 hr. 1 day 3 days 5 days 7 days 0 days Caking 88None... 2, 2, 00 Hard set 129. 0 u 3,300 o 127-.. .-do

4, 700 5, 000 a, 800 3,800 3,800 3, 400 Do, 175 ..do 6, 600 6, 000 4,800 5, 600 4, 500 4,200 Do. 175.-. Crude cocoanut oil methyl ester C 0,kaolin. 0.5, 2. 5 2, 100 2, 300 2,000 1, 000 1, 700 1, 500 Non-oaking.88 Sodium bisulfate 8 1,500 Hard set. 129 .do .05 18 28 28 2 338 Do, 127.-do 0- 06 18 18 84 450 850 900 D0, 175.. Crude cocoanut oil methylester Cir-Cu, kaolin, sodium 0.5, 2. 5 18 188 357 357 460 Non-caking.

bisulfate. 0.05 88 Ammonium bisulfatc- 0. 03 Hard set. 129... ..do tH15Do. 127.-. 00 Do. 88.-.. 03 Do. 129... ..do o. 05 100... ..do 0.1 Talloil. 0.05 1, 000 0, 5 282 Do.

Limit; of test 18 p.p.m. *Titration to pH 8.3 with hydrochloric acid.

TABLE 3 One month hag storage tests for coated urea microprills Weightof lumps in Hardness of lumps lb. bag

'1 rcatmcnt I After number Conditioner As 15 dropping As 15 Afterdropping 80 .llard. *oanut oil methyl ester. 2 5. 7 Medium-hard. Medium030% crude cocoanut oil methyl ester 0.5 Mcdiunrhard Do 25 calciumstoarate 0.37 crude cocoanut oil methyl ester, kaolin. 0 Medium. Frooflowing. 0.37% crude cocoanut oil methyl esto 41% kaolii CompletelyCompletely free flowing. 0.51'7 crude cocoanut oil methyl ester. I 7. 7h/lcdium-hard. Medium-hard. 0.51% crude cocoanut oil methyl ester, 2 2.7Medium Medium. 0.40% crude cocoanut oil methyl ester, 0,0 Completelyfree flowing. Completely free flowing. 0.75% crude cocoanut oil methylester, Z, kaolin 21.8 0 Medium. Free flowing. 0.75% crude cocoanut oilmethyl ester, 2.28% kaolin. 0,0 Completely free flowing. Completely freeflowing. 0.20% calcium stt-arato, 0.20% guar gum Nittilllllll Mfldllglm.

12 Normal urea (kaolin coated) Those data show that treatments 5, 8 and10 produce a completely free flowing urea product, however, a strongammonia odor prevailed in the storage area.

TABLE 4 Three month 1mg storage tests [or rented urea inieropril.

Weight of lumps in 80 lb. 1mg Hardness ol' lumps Treatment After After Inumber Conditioner As is dropping As is dropping 1 None 80.0 26.5 Veryhard"... Very hard. 2- 0.39% crude cocoanut oil methyl ester 28. 5 O. 5Hard Medium. 3A.. 0.38% crude cocoanut oil methyl ester, 5% 31.5 0.5Medium-hard Medium-soft. 4.. 0.37% crude cocoanut oil methyl ester,0.24% koalin 17. 5 1. 5 Medium-hard o. 5 0.37% crude cocoanut oil methylester, .41% aolin 5. 0 0 Soft Free flowing. 6-- 0.51% crude cocoanut oilmethyl ester 12, 5 0, 5 Medium Medi v 7.. 0.51% crude cocoanut oilmethyl ester, 0 5. 5 0 Medhnn- Free llowing. 8 0.49% crude cocoanut oilmethyl ester, 2 0% kaolin 2.5 0 Soft i [)o. 0.. 0.75% crude cocoanut oilmethyl ester, (1-5% kaolin 11.0 0. 5 Medium Medium-soft. 10 0.75% crudecocoanut oil methyl ester, 2.28% kaolin 1.5 o Medium-soft Free flowing.11... 0.26% calcium steal-ate, 0.26% gum gum 311. 0 1. 5 Medium-hardHard. 12 Normal urea (kaolin coated) 24.0 3.0 lvlerliuin-selt.

EXAMPLE 4 EXAMPLE 6 500 to 1,000 pound samples of feed-grade ureamicroprills, 93% mesh +60 mesh, are charged to a conventional typeblender and sprayed with approximately 0.5 percent by weight of crudecocoanut oil methyl ester having from 16-18 carbon atoms and marketedunder the trademark Stepan C-65. Blending is continued untilsubstantially uniform coating is achieved. 2.5 percent by weight offinely divided kaolin and from 0.02 to 0.22 percent by weight of sodiumbisulfate (100% 100 microns) is then charged to the agitated bed ofcoated urea and thoroughly blended therewith. The thus prepared productis bagged in standard 80 pound bags and stored in conventional storagefacilities. Each composition is examined daily for seven days and theconcentration of ammonia in the confined air space over the samplesdetermined. Data obtained Ten tons of prilled urea (8-14 mesh) ar'esprayed with crude cocoanut methyl ester at a rate of 0.5 percent byweight of urea while being conveyed from the prilling tower to thestorage shed. The conveying equipment serves to blend the methyl esterand urea so that the prills discharged in the shed are uniformly coatedand are ready for further mixing with 0.1 percent sodium acid sulfateand 0.5 percent kaolin to yield a final product for bagging and storage.The thus prepared product is found to be non-caking and odor free.

We claim:

1. An odor free, non-caking, conditioned urea composition comprising:

1. at least about 95 percent by weight of finely divided urea;

are reported below. 2. from about 0.1 to 1.0 percent by weight of a Todetermine the amount of ammonium salts in th methyl ester selected fromthe group consisting of original samples as ppm. NH the ammonium saltsare i. crude cocoanut oil methyl esters and tallow fatty converted tothe acids of the salts with formaldehyde acid methyl esters having from12 to 18 carbon and measured by an acid-base titration. atoms; and

TABLE 5 [Tests showing ammonia concentration above treated productrelated to free ammonia and ammonium saltsin original product]Concentration of ammonia Free Ammonium (p.p.1n.) that Ammoniaconcentration in confined air space over ammonia salts in Additives(percent) sodium sample, at 1*., p.p.in. in original original hisnllateI sample sample as Methyl will Alter After Alter Alter Alter Alter AfterSample (p.p.m.) p.p.m. N11 Clay ester NallSO4 neutralize 1 day 2 daysdays 4 days 5 days 0 days 7 days *Sample 2 breakthrough of ammoniaoccurred after 6 days. Sample 7 no breakthrough of ammonia detectedafter 10 days. "*Sample 8 no breakthrough of ammonia detected after 17days. 1 Crude cocoanut oil methyl ester.

2 Sodium bisulfate.

All samples completely free flowing.

EXAMPLE 5 ii. methyl esters of unsaturated fatty acids of a cisconfiguration containing from 18 to 22 carbon 60 atoms and up to twodouble bonds; and

3. from about 0.01 to 0.5 percent by weight of a water soluble acid saltselected from the group consisting of sodium bisulfate, ammonium 65bisulfate, and monoammonium phosphate.

2. A composition according to claim 1 wherein saidcomposition containsin addition to said methyl ester and acidic salt, from about 0.25 to 2.5percent by weight of finely divided clay.

3. A composition according to claim 1 wherein said methyl ester is saidcocoanut oil methyl ester and has from about 16 to 18 carbon atoms.

4. A composition according to claim 1 wherein said methyl ester ismethyl oleate or methyl linoleate.

5. A composition according to claim 1 wherein said acid salt is sodiumbisulfate and said methyl ester is said cocoanut oil methyl ester, andis present in said composition in an amount from about 0.25 to 0.75percent by weight of said composition.

6. An odor free, non-caking, conditioned urea according to claim 1comprising: at least about 95 percent by weight of finely divided urea,from about 0.25 percent to about 0.75 percent by weight of a crudecocoanut oil methyl ester having from 16 to 18 carbon atoms, from about0.05 to 0.2 percent by weight of an acidic salt selected from the groupconsisting of sodium bisulfate, ammonium bisulfate, and monoammoniumphosphate and from about 0.25 to 2.5 percent by percent to about 0.75percent by weight of a methyl ester selected from the group consistingof methyl oleate and methyl linoleate, from about 0.05 to 0.2 percent byweight of an acidic salt selected from the group consisting of sodiumbisulfate, ammonium bisulfate and monoammonium phosphate and from about0.25 to 2.5 percent by weight of finely divided kaolin.

UNITED. STATES PATENT OFFICE CERTIFICATE OF CGRRECTWN Patent No.5,689,551 Dated September 5 1972 Paul R. Patterson; Darryl D. Fry andIrving Klothen.

Inventor(s It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 1, after the inventors addresses, insert Assignors to AmericanCyanamid Company, Stamford, Gonn.-

Signed and sealed this 3rd day of April 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTS CHALK Attesting Officer Commissionerof Patents- "ORM PO1050(10-69) USCOMM-DC 60376-P69 Uri. GovimmzwrHUNTING orrlcz nu o-su-an

2. A composition according to claim 1 wherein said composition contains in addition to said methyl ester and acidic salt, from about 0.25 to 2.5 percent by weight of finely divided clay.
 2. from about 0.1 to 1.0 percent by weight of a methyl ester selected from the group consisting of i. crude cocoanut oil methyl esters and tallow fatty acid methyl esters having from 12 to 18 carbon atoms; and ii. methyl esters of unsaturated fatty acids of a cis configuration containing from 18 to 22 carbon atoms and up to two double bonds; and
 3. from about 0.01 to 0.5 percent by weight of a water soluble acid salt selected from the group consisting of sodium bisulfate, ammonium bisulfate, and monoammonium phosphate.
 3. A composition according to claim 1 wherein said methyl ester is said cocoanut oil methyl ester and has from about 16 to 18 carbon atoms.
 4. A composition according to claim 1 wherein said methyl ester is methyl oleate or methyl linoleate.
 5. A composition according to claim 1 wherein said acid salt is sodium bisulfate and said methyl ester is said cocoanut oil methyl ester, and is present in said composition in an amount from about 0.25 to 0.75 percent by weight of said composition.
 6. An odor free, non-caking, conditioned urea according to claim 1 comprising: at least about 95 percent by weight of finely divided urea, from about 0.25 percent to about 0.75 percent by weight of a crude cocoanut oil methyl ester having from 16 to 18 carbon atoms, from about 0.05 to 0.2 percent by weight of an acidic salt selected from the group consisting of sodium bisulfate, ammonium bisulfate, and monoammonium phosphate and from about 0.25 to 2.5 percent by weight of finely divided kaolin.
 7. A composition according to claim 1 wherein said acid salt is sodium bisulfate and said methyl ester is present in said composition in an amount from about 0.25 percent to 0.75 percent by weight of said composition.
 8. An odor free, non-caking, conditioned urea according to claim 1 comprising: at least about 95 percent by weight of finely divided urea, from about 0.25 percent to about 0.75 percent by weight of a methyl ester selected from the group consisting of methyl oleate and methyl linoleate, from about 0.05 to 0.2 percent by weight of an acidic salt selected from the group consisting of sodium bisulfate, ammonium bisulfate and monoammonium phosphate and from about 0.25 to 2.5 percent by weight of finely divided kaolin. 